Chult

Chult is located on a large island in the southern part of The Trackless Sea, off the coast of the Chultan peninsula. It is a mountainous jungle of savage beasts, hulking dinosaurs, and disease-ridden swamps. Savage human tribes, goblins, and even stranger monstrous folk haunt the thick jungles. Nevertheless, Chult draws adventurers who search for its legendary riches. The primordial Ubtao is almost exclusively revered in the land, for the divine powers of Faerûn awarded Ubtao the dominion over the land of Chult in exchange for the deity's vigilance over the threat from under the Peaks of Flame. It has also historically been known as a safe haven for pirates.
It is said by many that the jungles of Chult are the most dangerous places in Faerûn. The plants are intelligent predators while the predators themselves are massive and armed with huge teeth and claws. Insects bite and sting travelers almost constantly, the heat and humidity is almost unbearable and the undergrowth contains a multitude of poisonous snakes. Worst, however is the disease that runs rampant in the area. Most things in the jungle have some sort of illness or parasite and it is very easy to catch such illnesses off them. Even the water is tainted and must be boiled if you wish to drink. On top of all this, the intelligent creatures that eke out an existence in the dense foliage are perfectly happy (and sometimes go out of their way) to track travelers in order to hunt them down and kill them. Yuan-ti, batiri, and other species that have learned to survive in this place need food and adventurers tend to suit that need nicely.
Yet those adventurers keep on coming in their droves to the Chultan jungles as rumours of endless veins of gold, huge gems and ruined empires stuffed to the brim with magic and riches keep surfacing in taverns across Faerûn and many are willing to brave the dangers of the jungle for a slice of that fabled wealth.